More questions about my Intrepid?

Last week I asked about some diagnosis possibilites for a 2001 Intrepid. The response was I needed spark, compression, and fuel. I have compression and fuel and we have determined that there is a coil for each spark plug because there is no distributor. It sounds like the starter is not engaging but not sure about that. We put a coil tester on one of the coils and didnt' get a spark. So a couple of questions. If the starter is bad, would it prevent the coils from getting spark? And then second if one coil is bad, would it prevent the other coils from getting spark? We are kinda stumped on what just made the car shut off going down the road and now it doesn't run. Thanks for your suggestions.